Ambient Backscatter: Plucking Wireless Power from TV Signals

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ambient-backscatter-transponder-front-back-640x353Researchers at the University of Washington have gotten one step closer to the fabled “Internet of Things,” where everything — and I do mean everything — is connected to everything else.  One of the main issues they’ve conquered is the sad fact that all wireless devices, at some point, require a wire to provide them power, or at the very least they need to have their batteries replaced. The technology the researchers developed is called ambient backscatter, and it works by harvesting radio frequency (RF) energy present in the atmosphere to power a small device — that’s where the “ambient” portion of the name comes from.

The device then processes and reflects the energy back out in a way that allows it to communicate with other devices — hence the “backscatter” portion of the name. Ambient backscatter devices literally pull power from thin air.

And, yes, harvesting and retransmitting RF energy is perfectly legal.  According to the researchers, their ambient backscatter devices fall under the same governance as another very popular battery-free device: RFID tags. This is different from RFID tags, though, which either require a power source or a reader nearby to energize the tag. Because these devices emit RF radiation at incredibly low levels (microwatts), and because they’re not actively generating a signal in a reserved block of spectrum, they’re not regulated by the FCC.

This is a fairly big deal, as ambient backscatter technology could allow small transceivers and sensors to be embedded in pretty much anything, and they would just run from the power generated by all the communication devices that already blanket the planet.  The possibilities are really endless for this type of technology, but as with their RFID tag predecessors, it’ll likely be a while before they’re seen in the home.

Check out more of the details at the source story.

Via: [ExtremeTech]

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